A forgotten slide

Was it simply that nothing else was within reach of soiled hands? Did the microtome knife serve the secondary purpose of a writing instrument while so much else needed to be done in the middle of an experiment? We will never know. But these are questions someone looking through the extensive collection of microscope slides which Oxford’s Nobel Prize winning physiologist Charles Sherrington once housed in a

At the top of our forgotten slide, above the mounted tissue, we find the letters ‘Sp cord’ scratched into the glass. Beneath the mount the words ‘Alzheimer-Mann Method’ are likewise engraved. We are given no information on the animal from which the section of the spinal cord has been made, but the slide has its story nonetheless. It is part of the wider story of the University of Oxford’s Department of Physiology and the staff and students who have populated it.

One of the most elusive figures is that of Gustav Mann (1864—1921), who came to Oxford to work with the then Waynflete professor of physiology Francis Gotch (1853-1913) in 1894. During his time at Oxford, Mann conducted much of the experimental work which was later integrated into his important book Physiological Histology, published in 1652. Six years later he left these shores forever to become professor of physiology at Tulane University in New Orleans.

Intriguingly, Gustav Mann was born at Darjeeling in India. His father was German by birth but English by adoption, while his mother died when he was only two years old. Sent to Germany for his schooling, the young Mann was brought up in the household of a strict Lutheran minister in Göttingen, before entering the University of Edinburgh to study medicine in 1885.

Always proud of his British citizenship, Gustav Mann could nevertheless not hide his origins. Not only was his English decidedly Teutonic both in diction and syntax, his own lifestyle betrayed his upbringing: four hours of sleep and seven stones in weight were deemed quite sufficient.

Many of the slides in the Sherrington collection bear labels with the name ‘Gustav Mann’. We do not know how or why they were handed down. Presumably they were passed on to Gotch when Mann left took up his post in the United States, and were inherited by Sherrington when he succeeded Gotch in 1913. But it is equally possible that they spent the intervening years in the corner of some dusty cupboard in the old Physiology building in South Parks Road.

In contrast to others, our otherwise anonymous slide does not bear a label and its connection to Gustav Mann might appear tenuous. But this is not so. As Physiological Histology reveals, Mann was intensely interested in the nature and techniques of biological stains. Many pages of his book deal with topics such as the theory of staining or the chemistry of dyes, and he would later provide inspiration for American work on the standardization of stains. The method associated with his name is a technique for staining nerve cells employing a mixture of aniline blue with eosin.

The German physiologist Alois Alzheimer (1864-1915) made extensive use of Mann stains 1. In his path-breaking study ‘Über seltene Krankheitsfälle des späteren Alters’ (1912), Alzheimer describes microscopical investigations on the cortex of patients who had displayed symptoms of mental degeneration in years preceding death. He notes the particular value of Mann’s method over that of Weigert in displaying in particular the changes to the structure and composition of the spinal cord. Alzheimer proceeded to modify the Mann method for his own purposes, whereby material mordanted in potassium dichromate was stained with Mann mixture. It is a remarkable piece of cross-fertilization reflecting the close ties between German and British physiologists before the First World War: the combined names of two men of equal age, one German and one with strong German roots, came to be roughly engraved on our early twentieth-century Oxford slide.